CHARACTERIZATION OF AN INTRONLESS COLLAGEN GENE FAMILY IN THE MARINE SPONGE MICROCIONA-PROLIFERA
CHARACTERIZATION OF AN INTRONLESS COLLAGEN GENE FAMILY IN THE MARINE SPONGE MICROCIONA-PROLIFERA
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DOI：
10.1073/pnas.90.15.7288
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发表时间：
1993-08-01
影响因子：
11.1
通讯作者：
BOEDTKER, H
中科院分区：
文献类型：
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作者：
AHO, S;TURAKAINEN, H;BOEDTKER, H
通过与秀丽隐杆线虫Col-1基因杂交，从海绵Microciona prolifera的基因组DNA中分离到两个独立的克隆，通过PCR从基因组DNA中获得一个克隆。它们含有开放阅读框架（MpCol 1，MpCol 2，MpCol 3，MpCol 4），能够编码不同于以前在海绵中发现的胶原蛋白家族。基因组DNA的Southern印迹表明存在其他几个同源基因。通过特异性引物和反向PCR技术，获得了MpCol 1的大部分三螺旋编码区和3'非翻译区的cDNA克隆。两个cDNA克隆在MpCol 1的翻译终止密码子下游170 bp的AATAAA序列的中间结束。推测的NH 2-末端非胶原肽仅由7个氨基酸残基组成。1074-bp的三螺旋编码区不被间插序列中断。它编码120个Gly-Xaa-Yaa三联体的多肽，在COOH末端附近只有一个短的中断。一个假定的N-糖基化序列（Asn-Gly-Ser），三个Arg-Gly-Asp三联体（称为细胞识别肽），常见的Lys残基在Yaa位置（这是羟基化的模板），几个Lys-Gly-Asn/Xaa-Arg肽（称为赖氨酰氧化酶识别位点），以及长链无亚氨基酸可以在三螺旋结构域中发现。短的COOH末端非胶原结构域非常类似于线虫表皮胶原和脊椎动物非纤维胶原。我们的研究结果有力地支持了这样的观点，即在高等生物中发现的胶原蛋白基因和基因家族的多样性已经存在于海绵中。
Two independent clones from the genomic DNA of a marine sponge Microciona prolifera were isolated by hybridization to the Caenorhabditis elegans Col-1 gene and one clone was obtained from genomic DNA by PCR. They contain open reading frames (MpCol1, MpCol2, MpCol3, MpCol4) capable of coding for a family of collagens different from those previously found in sponges. Southern blotting of genomic DNA suggested the presence of several other homologous genes. cDNA clones covering most of the triple-helical coding domain and the 3' untranslated region of MpCol1 were isolated by specific primers and reverse PCR. Two cDNA clones end in the middle of an AATAAA sequence 170 bp downstream from the translation stop codon of MpCol1. The putative NH2-terminal noncollagenous peptide is composed of only seven amino acid residues. The 1074-bp triple-helical coding region is not interrupted by intervening sequences. It codes for a polypeptide of 120 Gly-Xaa-Yaa triplets with only one short interruption near the COOH terminus. A putative N-glycosylation sequence (Asn-Gly-Ser), three Arg-Gly-Asp triplets known as cell recognition peptides, frequent Lys residues in the Yaa position (which are templates for hydroxylation), several Lys-Gly-Asn/Xaa-Arg peptides known as the lysyl oxidase recognition site, and long stretches without imino acids could be found within the triple-helical domain. The short COOH-terminal noncollagenous domain closely resembles that of nematode cuticular collagens and vertebrate nonfibrillar collagens. Our results strongly support the idea that the diversity of collagen genes and gene families found in higher organisms already existed in sponge.